Inhibition Of P38 MAPK Activity Research Articles

The neo-potential therapeutic strategy in preeclampsia: downregulated miR-26a-2-3p motivates endothelial cell injury by targeting 15-LOX-1

Preeclampsia (PE) poses a life-threatening risk for both mothers and babies, and its onset and progression are linked to endothelial injury. The enzyme 15-lipoxygenase-1 (15-LOX-1), critical in arachidonic acid metabolism, is implicated in various diseases, yet its specific role and precise mechanisms in PE remain largely unknown. In this study, we found that 15-LOX-1 and its main metabolite, 15-HETE, were significantly increased in both the placenta and serum of PE patients. This increase was accompanied by elevated levels of endothelial injury markers, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). A positive correlation between 15-LOX-1 and those markers in the placenta. In Alox15-/- mice, Alox15 deficiency reduced endothelial cell injury in PE-like mice induced by L-NAME. In vitro studies showed that hypoxia-induced upregulation of 15-LOX-1 reduced the cell viability, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs), while increasing apoptosis and inflammatory cell adhesion. Mechanistically, the p38 MAPK pathway was identified as a downstream target of 15-LOX-1. Knocking down 15-LOX-1 or inhibiting p38 MAPK activation improved endothelial cell injury in hypoxia-treated HUVECs. Furthermore, downregulation of miR-26a-2-3p was found to correlate negatively and colocalize with 15-LOX-1 upregulation in the placenta of PE patients. Luciferase reporter assays further confirmed that miR-26a-2-3p directly bind to the 3’UTR of 15-LOX-1, targeting its expression. Moreover, miR-26a-2-3p agomir ameliorated the PE-like phenotype in mice through the 15-LOX-1/p38 MAPK axis, improving endothelial dysfunction. Therefore, our study provides novel insights into the pathogenesis of PE and highlight modulating the miR-26a-2-3p/15-LOX-1/p38 MAPK axis as a potential therapeutic target for PE.

Emerging Molecular and Synaptic Targets for the Management of Chronic Pain Caused by Systemic Lupus Erythematosus.

Patients with systemic lupus erythematosus (SLE) frequently experience chronic pain due to the limited effectiveness and safety profiles of current analgesics. Understanding the molecular and synaptic mechanisms underlying abnormal neuronal activation along the pain signaling pathway is essential for developing new analgesics to address SLE-induced chronic pain. Recent studies, including those conducted by our team and others using the SLE animal model (MRL/lpr lupus-prone mice), have unveiled heightened excitability in nociceptive primary sensory neurons within the dorsal root ganglia and increased glutamatergic synaptic activity in spinal dorsal horn neurons, contributing to the development of chronic pain in mice with SLE. Nociceptive primary sensory neurons in lupus animals exhibit elevated resting membrane potentials, and reduced thresholds and rheobases of action potentials. These changes coincide with the elevated production of TNFα and IL-1β, as well as increased ERK activity in the dorsal root ganglion, coupled with decreased AMPK activity in the same region. Dysregulated AMPK activity is linked to heightened excitability in nociceptive sensory neurons in lupus animals. Additionally, the increased glutamatergic synaptic activity in the spinal dorsal horn in lupus mice with chronic pain is characterized by enhanced presynaptic glutamate release and postsynaptic AMPA receptor activation, alongside the reduced activity of glial glutamate transporters. These alterations are caused by the elevated activities of IL-1β, IL-18, CSF-1, and thrombin, and reduced AMPK activities in the dorsal horn. Furthermore, the pharmacological activation of spinal GPR109A receptors in microglia in lupus mice suppresses chronic pain by inhibiting p38 MAPK activity and the production of both IL-1β and IL-18, as well as reducing glutamatergic synaptic activity in the spinal dorsal horn. These findings collectively unveil crucial signaling molecular and synaptic targets for modulating abnormal neuronal activation in both the periphery and spinal dorsal horn, offering insights into the development of analgesics for managing SLE-induced chronic pain.

PCSK9 increases vulnerability of carotid plaque by promoting mitochondrial dysfunction and apoptosis of vascular smooth muscle cells.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recognized as a novel lipid-lowing target. Recent clinical studies suggested the value of inhibiting PCSK9 in decreasing the vulnerability of coronary plaques. However, the evidence of PCSK9-regulated evolution of unstable carotid plaques is unclear, which has limited the use of PCSK9 inhibitor in carotid plaques. This study aimed to determine the effect and molecular mechanisms of PCSK9 on vulnerability of carotid plaques, to provide potential therapeutic targets for stabilizing carotid plaques. The expression of PCSK9 in stable and unstable carotid plaques were examined in tissue and plasma. Human aortic vascular smooth muscle cells (VSMCs) and carotid VSMCs were employed to transfect lentivirus for overexpression and knockdown of PCSK9, respectively. Morphological and functional changes of mitochondria were observed by live-cell imaging. Cell apoptosis was evaluated by propidium iodide staining. RNA-sequencing and biological examinations were performed to explore and validate the underlying mechanisms. Truncated plasmids were employed to identify the functional domain of PCSK9 in regulation of VSMCs' mitochondrial morphology, function and apoptosis. Clinically, PCSK9 was closely related with vulnerability of human carotid plaques. Increased expression of PCSK9 in human VSMCs was accompanied by higher level of apoptosis. At subcellular level of VSMCs, the morphology of mitochondria was shifted toward the fission state, followed by mitochondrial dysfunction. Inhibition of p38 MAPK activation partially rescued the above morphological and behavioral changes caused by PCSK9. Furthermore, inhibiting of dynamin-related protein 1 (DRP1) attenuated PCSK9-related mitochondrial dysfunction and cell apoptosis. The 1-149aa domain of PCSK9 protein was essential to achieve functional regulation to VSMCs. Our findings demonstrated that PCSK9 induced morphology-related mitochondrial dysfunction and apoptosis of VSMCs, which may be related to increased vulnerability of carotid plaque.

The CoREST repressor complex mediates phenotype switching and therapy resistance in melanoma.

Virtually all patients with BRAF-mutant melanoma develop resistance to MAPK inhibitors largely through nonmutational events. Although the epigenetic landscape is shown to be altered in therapy-resistant melanomas and other cancers, a specific targetable epigenetic mechanism has not been validated. Here, we evaluated the corepressor for element 1-silencing transcription factor (CoREST) epigenetic repressor complex and the recently developed bivalent inhibitor corin within the context of melanoma phenotype plasticity and therapeutic resistance. We found that CoREST was a critical mediator of the major distinct melanoma phenotypes and that corin treatment of melanoma cells led to phenotype reprogramming. Global assessment of transcript and chromatin changes conferred by corin revealed specific effects on histone marks connected to epithelial-mesenchymal transition-associated (EMT-associated) transcription factors and the dual-specificity phosphatases (DUSPs). Remarkably, treatment of BRAF inhibitor-resistant (BRAFi-R) melanomas with corin promoted resensitization to BRAFi therapy. DUSP1 was consistently downregulated in BRAFi-R melanomas, which was reversed by corin treatment and associated with inhibition of p38 MAPK activity and resensitization to BRAFi therapies. Moreover, this activity was recapitulated by the p38 MAPK inhibitor BIRB 796. These findings identify the CoREST repressor complex as a central mediator of melanoma phenotype plasticity and resistance to targeted therapy and suggest that CoREST inhibitors may prove beneficial for patients with BRAFi-resistant melanoma.

Heat shock induces HuR-dependent MKP-1 posttranslational regulation through the p38 MAPK signaling cascade

Previous studies demonstrated that phosphatases play a pivotal role in modulating inflammation-associated signal transduction, particularly in the context of heat shock, where Mitogen-Activated Protein Kinase Phosphatase-1 (MKP-1) appears to have a central role. Recently, Human Antigen R (HuR) has also been identified as a factor that enhances stress-response protein MKP-1 levels. Consequently, we have directed our interest towards elucidating the mechanisms by which heat shock induces MKP-1 mRNA stabilization, dependent on HuR via the p38 MAPK Signaling Cascade. In this study, we subjected Mouse Embryonic Fibroblast (Mef) cells to heat shock treatment, resulting in a potent stabilization MKP-1 mRNA. The RNA-binding protein HuR, known to influence mRNA, was observed to bind to the MKP-1 AU-rich 3 ´untranslated region. Transfection of p38 wild-type Mef cells with a flag-HuR plasmid resulted in a significant increase in MKP-1 mRNA stability. Interestingly, transfection of the siRNA for HuR into Mef cells resulted in diminished MKP-1 mRNA stability following heat shock, inhibition of p38 MAPK activity effectively curtailed heat shock-mediated MKP-1 mRNA stability. Immunofluorescence analyses further revealed that the translocation of HuR was contingent on p38 MAPK Signaling Cascade. Collectively, these findings underscore the regulatory role of heat shock in MKP-1 gene expression at posttranscriptional levels. The mechanisms underlying the observed increased MKP-1 mRNA stability are shown to be partially dependent on HuR through the p38 MAPK Signaling Cascade.

High-Frequency Repetitive Magnetic Stimulation Activates Bactericidal Activity of Macrophages via Modulation of p62/Keap1/Nrf2 and p38 MAPK Pathways.

The effects of repetitive magnetic stimulation (rMS) have predominantly been studied in excitable cells, with limited research in non-excitable cells. This study aimed to investigate the impact of rMS on macrophages, which are crucial cells in the innate immune defense. THP-1-derived macrophages subjected to a 5 min session of 10 Hz rMS exhibited increased Nrf2 activation and decreased Keap1 expression. We found that activation of the Nrf2 signaling pathway relied on rMS-induced phosphorylation of p62. Notably, rMS reduced the intracellular survival of Staphylococcus aureus in macrophages. Silencing Nrf2 using siRNA in THP-1-derived macrophages or utilizing Nrf2 knockout in alveolar macrophages abolished this effect. Additionally, rMS attenuated the expression of IL-1β and TNF-α inflammatory genes by S. aureus and inhibited p38 MAPK activation. These findings highlight the capacity of rMS to activate the non-canonical Nrf2 pathway, modulate macrophage function, and enhance the host's defense against bacterial infection.

BCL2L1 inhibitor A-1331852 inhibits MCL1 transcription and triggers apoptosis in acute myeloid leukemia cells

BH3 mimetics exert anticancer activity by inhibiting anti-apoptotic BCL2 proteins. However, accumulating evidence indicates that the off-target effects of these drugs tightly modulates their anticancer activities. In this study, we investigated whether the BCL2L1 inhibitor A-1331852 induced the death of U937 acute myeloid leukemia (AML) cells through a non-BCL2L1-targeted effect. A-1331852-induced apoptosis in U937 cells was characterized by increased ROS production, downregulation of MCL1, and loss of mitochondrial membrane potential. Ectopic expression of MCL1 alleviated A-1331852-induced mitochondrial depolarization and cytotoxicity in U937 cells. A-1331852-induced ROS production increased p38 MAPK phosphorylation and inhibited MCL1 transcription. Inhibition of p38 MAPK activation restored MCL1 expression in A-1331852-treated cells. A-1331852 triggered p38 MAPK-mediated Cullin 3 downregulation, which in turn increased PP2Acα expression, thereby reducing CREB phosphorylation. A-1331852 reduced the binding of CREB to the MCL1 promoter, leading to the inhibition of CREB-mediated MCL1 transcription. Furthermore, A-1331852 acted synergistically with the BCL2 inhibitor ABT-199 to induce U937 and ABT-199-resistant U937 cell death by inhibiting MCL1 expression. A similar phenomenon caused A-1331852-induced MCL1 downregulation and cytotoxicity in AML HL-60 cells. Collectively, our data suggest that A-1331852 shows an off-target effect of inhibiting MCL1 transcription, ultimately leading to U937 and HL-60 cell death.

Chlorogenic Acid Alleviates Chronic Stress-Induced Intestinal Damage by Inhibiting the P38MAPK/NF-κB Pathway.

Chronic stress can cause intestinal barrier damage. MAPK and NF-κB are closely related to it. Chlorogenic acid (CGA), a dietary polyphenol, has been shown to have intestinal protective effects, but whether by regulating MAPK and NF-κB is not known. Therefore, in this experiment, 24 Wistar rats were randomly divided into 4 groups (C group, CS group, CS + SB203580, and CS + CGA group). Rats in the CS group were restrained stress for 6 h per day for 21 days. Rats in the CS + SB203580 group were given SB203582 (0.5 mg/kg, intraperitoneal injection) 1 h before restraint stress every other day. Rats in the CS + CGA group were given CGA (100 mg/kg, gavage) 1 h before restraint stress. In chronic stress, intestinal barrier damage was evident, while being restored after CGA treatment. After chronic stress, the levels of p-P38 were increased (P < 0.01), while the levels of p-JNK and p-ERK were not changed. The levels of p-p38 were elevated after CGA treatment (P < 0.01). These results suggested that p38MAPK played an important role in chronic stress-induced intestinal injury, and CGA could inhibit p38MAPK activity. Therefore, we chose SB203582 (P38MAPK inhibitor) to elucidate the role of p38. After chronic stress, intestinal tight junction key proteins Occludin, ZO-1, and Claudin3 protein and gene expression were reduced (P < 0.01), while being elevated after CGA or SB203582 intervention (P < 0.05). After CGA treatment, the levels of p-IκB, p-p65, p-p38, and TNF-α were reduced (P < 0.01). SB203582 intervention reduced p-p65 and TNF-α levels significantly (P < 0.01). These results suggested that CGA could inhibit the NF-κB pathway by suppressing p38MAPK, thereby alleviating chronic stress-induced intestinal damage.

The tick saliva peptide HIDfsin2 promotes the tick-borne virus SFTSV replication in vitro by enhancing p38 signal pathway.

Pathogens co-evolved with ticks to facilitate blood collection and pathogen transmission. Although tick saliva was recently found to be rich in bioactive peptides, it is still elusive which saliva peptide promotes virus transmission and which pathways are invovled. Here, we used a saliva peptide HIDfsin2 and a severe fever with thrombocytopenia syndrome virus (SFTSV) both carried by the tick Haemaphysalis longicornis to elucidate the relationship between tick saliva components and tick-borne viruses. HIDfsin2 was found to promote the replication of SFTSV in a dose-dependent manner in vitro. HIDfsin2 was further revealed to MKK3/6-dependently magnify the activation of p38 MAPK. The overexpression, knockdown and phosphorylation site mutation of p38α indicated that p38 MAPK activation facilitated SFTSV infection in A549 cells. Moreover, the blockade of p38 MAPK activation significantly suppressed SFTSV replication. Differently, HIDfsin2 or pharmacological inhibition of p38 MAPK activation had no effect on a mosquito-borne Zika virus (ZIKV). All these results showed that HIDfsin2 specifically promoted SFTSV replication through the MKK3/6-dependent enhancement of p38 MAPK activation. Our study provides a new perspective on the transmission of tick-borne viruses under natural conditions, and supports that the blockade of p38 MAPK activation can be a promising strategy against the mortal tick-borne virus SFTSV.

Chinese herbal medicine alleviates the pathogenesis of polycystic ovary syndrome by improving oxidative stress and glucose metabolism via mitochondrial Sirtuin 3 signaling

BackgroundPolycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women, and the curative effects of its current management are not satisfactory. A formula of Chinese herbal medicine (CHM), called Bu-Shen-Tian-Jing Formula (BSTJF), has clinically shown beneficial effects in treating PCOS. PurposeThis study aimed to investigate the mechanism underlying BSTJF for treatment of PCOS. MethodsWhole blood samples were collected from women with PCOS treated and not treated with BSTJF (n = 5 per group). Whole transcriptome sequencing of leukocytes and untargeted metabonomic analysis of the plasma were performed. Three groups of 18 female Sprague-Dawley rats were randomly selected: control, PCOS, and BSTJF. A PCOS rat model was established using testosterone propionate. The estrous cycle; glucose tolerance; ovarian morphology; serum markers of oxidative stress; and expression of Sirtuin 3 (SIRT3), phospho-p38 mitogen-activated protein kinase, phosphatidylinositol 3-kinase (PI3K), and phospho-protein kinase B in the ovary were measured. Palmitate was initially applied to KGN cells, followed by freeze-dried BSTJF powder. The glucose uptake, reactive oxygen species (ROS) production, and protein levels of SIRT3, PI3K, and glucose transporter type 4 (GLUT4) were detected in KGN cells. ResultsThe transcriptomic and metabolomic profiles showed alterations in 572 genes and 73 metabolites in women with PCOS treated with BSTJF. The enriched pathways in women with PCOS treated with BSTJF were mainly involved in inflammation, insulin resistance, glucose and lipid metabolism, and neuro and associated signaling pathways. In PCOS rat models, BSTJF improved the estrous cycle, glucose tolerance, and ovarian morphology; relieved oxidative stress; increased ovarian SIRT3 expression; inhibited p38 MAPK activation; and promoted the activation of PI3K/AKT signaling in the ovary. In the in-vitro study with KGN cells, BSTJF rescued the palmitate-induced impaired glucose uptake and SIRT3 expression, reduced mitochondrial ROS production mediated by SIRT3, and restored the impaired insulin-induced PI3K/AKT signaling pathway. ConclusionBSTJF effectively alleviated the pathogenesis of PCOS by improving oxidative stress and glucose metabolism via mitochondrial SIRT3 and the following insulin signaling pathway. This study innovatively revealed the action mechanism of CHM in treating PCOS.

Periostin attenuates oxygen and glucose deprivation-induced death of mouse neural stem cells via inhibition of p38 MAPK activation

Promoting neural stem cells (NSCs) survival in the harsh niche is essential to cell replacement therapy for various central nervous system diseases. As an integral component of the extracellular matrix, Periostin (POSTN) has been shown to protect various cell types from hypoxia-ischemia damage. This study aimed to investigate the neuroprotective effects of POSTN on NSCs injury induced by oxygen and glucose deprivation (OGD). Under challenge with OGD, cell viability significantly decreased in cultured mouse NSCs, and supplement POSTN rescued cell viability in a concentration-dependent manner, as shown by CCK-8. TUNEL and propidium iodide/Hoechst staining showed that POSTN pretreatment protected NSCs against OGD-induced apoptosis. Western blot assay demonstrated that POSTN pretreatment inhibited cleavage of caspase-3 and restored the balance of Bcl-2/Bax. And pretreatment with cilengitide (an inhibitor of POSTN receptors) abolished the protective effect of POSTN. Further investigation demonstrated that supplement POSTN inhibited phosphorylation of p38 in a concentration-dependent manner. Moreover, the neuroprotective effect of POSTN was hampered by anisomycin, an activator of p38. We conclude that POSTN pretreatment in cultured mouse NSCs mitigated OGD-induced cell death, and inhibition of the p38 MAPK pathway might be one of the underlying mechanisms. Our findings may provide a novel strategy for enhancing both endogenous and exogenous NSCs survival after ischemia and hypoxia injury.

Atypical activation of signaling downstream of inactivated Bcr-Abl mediates chemoresistance in chronic myeloid leukemia.

Chronic myeloid leukemia (CML) epitomises successful targeted therapy, where inhibition of tyrosine kinase activity of oncoprotein Bcr-Abl1 by imatinib, induces remission in 86% patients in initial chronic phase (CP). However, in acute phase of blast crisis, 80% patients show resistance, 40% among them despite inhibition of Bcr-Abl1 activity. This implies activation of either Bcr-Abl1- independent signalling pathways or restoration of signalling downstream of inactive Bcr-Abl1. In the present study, mass spectrometry and subsequent in silico pathway analysis of differentiators in resistant CML-CP cells identified key differentiators, 14-3-3ε and p38 MAPK, which belong to Bcr-Abl1 pathway. Their levels and activity respectively, indicated active Bcr-Abl1 pathway in CML-BC resistant cells, though Bcr-Abl1 is inhibited by imatinib. Further, contribution of these components to resistance was demonstrated by inhibition of Bcr-Abl1 down-stream signalling by knocking-out of 14-3-3ε and inhibition of p38 MAPK activity. The observations merit clinical validation to explore their translational potential.

P38 MAPK-mediated loss of nuclear RNase III enzyme Drosha underlies amyloid beta-induced neuronal stress in Alzheimer's disease.

MicroRNAs (miRNAs) are small noncoding RNAs ubiquitously expressed in the brain and regulate gene expression at the post‐transcriptional level. The nuclear RNase III enzyme Drosha initiates the maturation process of miRNAs in the nucleus. Strong evidence suggests that dysregulation of miRNAs is involved in many neurological disorders including Alzheimer's disease (AD). Dysfunction of miRNA biogenesis components may be involved in the processes of those diseases. However, the role of Drosha in AD remains unknown. By using immunohistochemistry, biochemistry, and subcellular fractionation methods, we show here that the level of Drosha protein was significantly lower in the postmortem brain of human AD patients as well as in the transgenic rat model of AD. Interestingly, Drosha level was specifically reduced in neurons of the cortex and hippocampus but not in the cerebellum in the AD brain samples. In primary cortical neurons, amyloid‐beta (Aβ) oligomers caused a p38 MAPK‐dependent phosphorylation of Drosha, leading to its redistribution from the nucleus to the cytoplasm and a decrease in its level. This loss of Drosha function preceded Aβ‐induced neuronal death. Importantly, inhibition of p38 MAPK activity or overexpression of Drosha protected neurons from Aβ oligomers‐induced apoptosis. Taken together, these results establish a role for p38 MAPK‐Drosha pathway in modulating neuronal viability under Aβ oligomers stress condition and implicate loss of Drosha as a key molecular change in the pathogenesis of AD.

Induction of G2/M Cell Cycle Arrest via p38/p21Waf1/Cip1-Dependent Signaling Pathway Activation by Bavachinin in Non-Small-Cell Lung Cancer Cells.

Lung cancer is the most commonly diagnosed malignant cancer in the world. Non-small-cell lung cancer (NSCLC) is the major category of lung cancer. Although effective therapies have been administered, for improving the NSCLC patient’s survival, the incident rate is still high. Therefore, searching for a good strategy for preventing NSCLC is urgent. Traditional Chinese medicine (TCM) are brilliant materials for cancer chemoprevention, because of their high biological safety and low cost. Bavachinin, which is an active flavanone of Proralea corylifolia L., possesses anti-inflammation, anti-angiogenesis, and anti-cancer activities. The present study’s aim was to evaluate the anti-cancer activity of bavachinin on NSCLC, and its regulating molecular mechanisms. The results exhibited that a dose-dependent decrease in the cell viability and colony formation capacity of three NSCLC cell lines, by bavachinin, were through G2/M cell cycle arrest induction. Meanwhile, the expression of the G2/M cell cycle regulators, such as cyclin B, p-cdc2Y15, p-cdc2T161, and p-wee1, was suppressed. With the dramatic up-regulation of the cyclin-dependent kinase inhibitor, p21Waf1/Cip1, the expression and association of p21Waf1/Cip1 with the cyclin B/cdc2 complex was observed. Silencing the p21Waf1/Cip1 expression significantly rescued bavachinin-induced G2/M cell accumulation. Furthermore, the expression of p21Waf1/Cip1 mRNA was up-regulated in bavachinin-treated NSCLC cells. In addition, MAPK and AKT signaling were activated in bavachinin-added NSCLC cells. Interestingly, bavachinin-induced p21Waf1/Cip1 expression was repressed after restraint p38 MAPK activation. The inhibition of p38 MAPK activation reversed bavachinin-induced p21Waf1/Cip1 mRNA expression and G2/M cell cycle arrest. Collectively, bavachinin-induced G2/M cell cycle arrest was through the p38 MAPK-mediated p21Waf1/Cip1-dependent signaling pathway in the NSCLC cells.

STK10 knockout inhibits cell migration and promotes cell proliferation via modulating the activity of ERM and p38 MAPK in prostate cancer cells.

Prostate cancer (PCa) is one of the most common types of cancer and is a serious threat to men's health due to the high rate of incidence and metastasis. However, the exact underlying pathology of this malignant disease has yet to be fully elucidated. The ezrin-radixin-moesin (ERM) family of proteins are associated with the development and metastasis of various types of cancer. Serine threonine kinase 10 (STK10) is an ERM kinase that is involved in the activation of ERM proteins and serves essential roles in the aggregation and adhesion of lymphocytes. To evaluate the functional roles of STK10 in the pathogenesis of PCa, a STK10-knockout (KO) DU145 PCa cell line was generated using the CRISPR-Cas9 gene editing system, and the effects of STK10 deletion on tumor biological behaviors were further analyzed. The present data suggested that STK10 KO promoted PCa cell proliferation by inhibiting p38 MAPK activation and suppressed migration primarily via the inhibition of p38 MAPK signaling and ERM protein activation. To the best of our knowledge, this is the first study to provide evidence that STK10 plays important roles in the proliferation and migration of PCa cells, which will be useful for further investigation into the pathogenesis of this disease.

Regulation of p38 MAPK and glucocorticoid receptor activation by hydrocortisone in mono-and co-cultured pancreatic acinar and stellate cells

Background/objectivesAcute pancreatitis develops as an inflammatory response to pancreatic tissue injury. Postoperative pancreatitis has recently been associated with increased occurrence of complications. Activation of the mitogen-activated protein kinase p38 (p38 MAPK) pathway occurs early in acute pancreatitis and its inhibition has been suggested to alleviate pancreatic inflammation. Glucocorticoids are potent anti-inflammatory steroids whose use in the management of acute pancreatitis remains controversial. Our aim was to examine the effect of crosstalk between pancreatic acinar cells (PACs) and stellate cells (PSCs) on p38 MAPK and glucocorticoid receptor (GR) activation and to assess the impact of hydrocortisone on these events. MethodsThe long-term co-culture setting for mouse PACs and PSCs developed in our laboratory was used. Parallel 4d mono- and co-cultures with or without 10 nM hydrocortisone were performed followed by immunocytochemical analysis of nuclear GR and phospho-p38 MAPK (pp38 MAPK). ResultsHydrocortisone inhibited pp38 MAPK up-regulation evoked by co-culture in PACs and PSCs and increased nuclear translocation of GR in PAC monocultures and in co-cultured PACs and PSCs. In PSC monocultures and co-cultured PACs, ligand-independent expression of nuclear GR was observed. In the former no change in nuclear GR but a significant decrease in total GR as analyzed by Western blot was caused by hydrocortisone. ConclusionsCellular microenvironment plays a significant role on p38 MAPK and GR activation in PACs and PSCs. Hydrocortisone is an effective means to inhibit p38 MAPK activation in PACs and PSCs. Both ligand-dependent and -independent regulatory roles for GR are suggested in the exocrine pancreas.

In silico screening of compounds from the Bahia semiarid region for identification of potential inhibitors of the p38 MAPK protein

The P38 MAPK protein is mainly involved in the synthesis of the proinflammatory cytokines IL1 and TNF-alpha and is important in the maintenance and amplification of the inflammatory process. Therefore, this protein presents high potential as a pharmacological target in the search for new treatments for inflammatory diseases. In silico approach has been of great importance to develop quick and inexpensive target identification and way to discover new bioactive molecules. This study used a computer ligand-docking method to screen the compounds from the Bahia semiarid region in silico for their ability to inhibit p38 MAPK activity. The protein crystallographic structure of the p38 MAPK was obtained from the Macromolecular Protein Data Bank. Northeast semiarid molecules were obtained from the ZINC database. The database was screened and a set of 233 molecules were selected as candidates using filtering based on parameters of the rule of Lipinski and Verber. The docking was carried out using the program Autodock Vina in its default configuration. The compound with ZINC databank code: 91596862 was found the most promising compound acoording to their binding free energy value obtained in the docking experiments (11,1 Kcal.mol-1) Intermolecular interactions analysis suggested that Van der Waals interactions are crucial to the ZINC molecule 69481892 in the active site of the p38 MAPK protein. Data resulting from all dockings are significant, although it has low accuracy. Thus, the hypothetical results of these in silico studies should be confirmed by in vitro and/or in vivo tests.

Ceramide accumulation accelerates nucleus pulposus cells degradation by p38MAPK activation.

Ceramide is a lipid molecule that regulates life activities such as cell differentiation, proliferation, apoptosis, and aging. However, whether ceramide plays a role in the intervertebral disc degeneration (IDD) is not clear. The aim of this study is to explore the effect of ceramide during the nucleus pulposus (NP) cells degeneration. We used human NP cells and passaged them until the fourth generation to analyze the content of ceramide. Cell-permeable C6-ceramide was used to upregulate ceramide expression, and myriocin was used to inhibit the accumulation of ceramide. To understand the relation between p38MAPK and ceramide, SB203580 was used to inhibit the activation of p38MAPK. We tested the viability of NP cells by the detection of collagen II and p16 expression, the proliferation, and the apoptosis of NP cells. Ceramide content was increased in NP cells from passage 1 (P1) to P4. The upregulation of ceramide accelerated the P1 NP cell degeneration by the reduction of collagen II production and proliferative cells population, increased p16 expression, and apoptotic cells population. However, the suppression of ceramide delayed the degeneration of P4 NP cells in the previous aspects. The accumulation of ceramide activated the phosphorylation of p38MAPK, and the inhibition of p38MAPK activation also alleviated the C6-ceramide-induced NP cell degeneration. Ceramide accumulates during NP cell degradation, and the upregulated ceramide contributes to the NP cells degeneration by p38MAPK activation.

Dexmedetomidine protects intestinal ischemia-reperfusion injury via inhibiting p38 MAPK cascades

Intestinal ischemia-reperfusion (I/R) is a life-threatening condition associated with high morbidity and mortality. Dexmedetomidine (DEX), an agonist of α2-adrenoceptor with sedation and analgesia effect, has recently been identified with protective function against I/R injury in multiple organs. However, the mechanism underlying the beneficial effect of DEX on intestine after I/R injury remained poorly understood. In the present study, using in both in vitro and in vivo models, we found that intestinal I/R injury was associated with the activation of p38 MAPK cascade, while DEX was capable of deactivating p38 MAPK and thus protect intestinal cells from apoptosis by inhibiting p38 MAPK-mediated mitochondrial depolarization and cytochrome c (Cyto C) release. Moreover, through inhibiting p38 MAPK activity, the downstream production of pro-inflammatory cytokines-regulated by NF-κB was also suppressed by DEX treatment, leading to the resolution of I/R-induced inflammation in intestine. In general, our study provided evidence that DEX protected intestine from I/R injury by inhibiting p38 MAPK-mediated mitochondrial apoptosis and inflammatory response.

Arsenic trioxide-induced p38 MAPK and Akt mediated MCL1 downregulation causes apoptosis of BCR-ABL1-positive leukemia cells

In this study, we investigated the mechanisms underlying arsenic trioxide (ATO)-induced death of human BCR-ABL1-positive K562 and MEG-01 cells. ATO-induced apoptotic death in K562 cells was characterized by ROS-mediated mitochondrial depolarization, MCL1 downregulation, p38 MAPK activation, and Akt inactivation. ATO-induced BCR-ABL1 downregulation caused Akt inactivation but not p38 MAPK activation. Akt inactivation increased GSK3β-mediated MCL1 degradation, while p38 MAPK-mediated NFκB activation coordinated with HDAC1 suppressed MCL1 transcription. Inhibition of p38 MAPK activation or overexpression of constitutively active Akt increased MCL1 expression and promoted the survival of ATO-treated cells. Overexpression of MCL1 alleviated mitochondrial depolarization and cell death induced by ATO. The same pathway was found to be involved in ATO-induced death in MEG-01 cells. Remarkably, YM155 synergistically enhanced the cytotoxicity of ATO on K562 and MEG-01 cells through suppression of MCL1 and survivin. Collectively, our data indicate that ATO-induced p38 MAPK- and Akt-mediated MCL1 downregulation triggers apoptosis in K562 and MEG-01 cells, and that p38 MAPK activation is independent of ATO-induced BCR-ABL1 suppression.